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 Freescale Semiconductor, Inc.
Order by AN1931/D
(Motorola Order Number)
Rev. 1, 3/03

3-Phase PM Synchronous Contents

1.0 Introduction of Application
Motor Vector Control using Benefit ...................................... 1
2.0 Motorola DSP Advantages and
DSP56F80x Features .................................... 2
3.0 Target Motor Theory................... 4
Design of Motor Control Application Based 3.1 Permanent Magnet Synchronous
Motor......................................... 4
on Motorola’s Software Development Kit
Freescale Semiconductor, Inc...

3.2 Mathematical Description of PM

Synchronous Motor................... 5
3.3 Digital Control of PM Synchronous
Libor Prokop, Pavel Grasblum Motor......................................... 9
Motorola Czech System Laboratories 4.0 System Concept ......................... 16
4.1 System Specification .............. 16
1. Introduction of Application 4.2 Vector Control Drive Concept 17
4.3 System Blocks Concept .......... 19
Benefit 5.0 Hardware Implementation ......... 28
5.1 Hardware Set-up ..................... 28
This Application Note describes the design of a 3-phase 6.0 Software Design ........................ 30
Permanent Magnet (PM) synchronous motor drive based on 6.1 Main Software Flow Chart ..... 30
Motorola’s DSP56F80x dedicated motor control device. The 6.2 Data Flow ............................... 35
software design takes advantage of the SDK (Software 6.3 State Diagram ......................... 41

3-Phase PM Synchronous Motor Vector Control

Development Kit) developed by Motorola. 7.0 Implementation Notes ............... 46
7.1 Scaling of Quantities .............. 46
PM synchronous motors are very popular in a wide
7.2 PI Controller Tuning............... 49
application area. The PM synchronous motor lacks a
7.3 Subprocesses Relation and State
commutator and is therefore more reliable than the DC motor.
Transitions............................... 49
The PM synchronous motor also has advantages when 7.4 Run/Stop Switch and Button
compared to an AC induction motor. Because a PM Control .................................... 50
synchronous motor achieves higher efficiency by generating 8.0 SDK Implementation ................ 52
the rotor magnetic flux with rotor magnets, a PM 8.1 Drivers and Library Function . 52
synchronous motors is used in high-end white goods (such as 8.2 Appconfig.h File..................... 52
refrigerators, washing machines, dishwashers); high-end 8.3 Drivers’ Initialization ............. 53
pumps; fans; and in other appliances which require high 8.4 Interrupts................................. 53
reliability and efficiency. 8.5 PC Master Software................ 53
The concept of the application is a speed closed-loop PM 9.0 DSP Memory Use ..................... 55
10.0 References ............................... 56
synchronous drive using a Vector Control technique. It serves
as an example of a PM synchronous motor control design
using a Motorola DSP with SDK support. It also illustrates
the use of the SDK’s dedicated motor control libraries.
This Application Note includes basic motor theory, system
design concept, hardware implementation and software
design, including the PC master software visualization tool.

© Motorola, Inc., 2003. All rights reserved.

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 Freescale Semiconductor, Inc.
Motorola DSP Advantages and Features

2. Motorola DSP Advantages and Features

The Motorola DSP56F80x family is well suited for digital motor control, combining the DSP’s
calculation capability with the MCU’s controller features on a single chip. These DSPs offer many
dedicated peripherals, such as Pulse Width Modulation (PWM) module(s), an Analog-to-Digital
Converter (ADC), Timers, communication peripherals (SCI, SPI, CAN), on-board Flash and RAM.
As an example, one member of the family, the DSP56F805, provides the following peripheral blocks:
• Two Pulse Width Modulator modules (PWMA & PWMB), each with 6 PWM outputs, 3
Current Sense inputs, and 4 Fault inputs; fault tolerant design with deadtime insertion,
supporting both center- and edge-aligned modes
• Twelve-bit Analog-to-Digital Converters (ADCs), supporting 2 simultaneous conversions
with dual 4-pin multiplexed inputs; the ADC can be synchronized by PWM modules
• Two Quadrature Decoders (Quad Dec0 & Quad Dec1), each with 4 inputs, or 2 additional
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Quad Timers A & B

• Two dedicated General Purpose Quad Timers totaling 6 pins: Timer C with 2 pins and Timer
D with 4 pins
• CAN 2.0 A/B Module with 2-pin ports used to transmit and receive
• Two Serial Communication Interfaces (SCI0 & SCI1), each with 2 pins, or 4 additional GPIO
lines
• Serial Peripheral Interface (SPI), with configurable 4-pin port, or 4 additional GPIO lines
• Computer Operating Properly (COP) timer
• Two dedicated external interrupt pins
• Fourteen dedicated General Purpose I/O (GPIO) pins, 18 multiplexed GPIO pins
• External reset pin for hardware reset
• JTAG/On-Chip Emulation (OnCE)
• Software-programmable, Phase Lock Loop-based frequency synthesizer for the DSP core
clock

Table 2-1. Memory Configuration

DSP56F801 DSP56F803 DSP56F805 DSP56F807

Program Flash 8188 x 16-bit 32252 x 16-bit 32252 x 16-bit 61436 x 16-bit

Data Flash 2K x 16-bit 4K x 16-bit 4K x 16-bit 8K x 16-bit

Program RAM 1K x 16-bit 512 x 16-bit 512 x 16-bit 2K x 16-bit

Data RAM 1K x 16-bit 2K x 16-bit 2K x 16-bit 4K x 16-bit

Boot Flash 2K x 16-bit 2K x 16-bit 2K x16-bit 2K x 16-bit

In addition to the fast Analog-to-Digital converter and the 16-bit Quadrature Timers, the most
interesting peripheral, from the PM synchronous motor control point of view, is the Pulse Width
Modulation (PWM) module. The PWM module offers a high degree of freedom in its configuration,
allowing efficient control of the PM synchronous motor.

2 3-Phase PM Synchronous Motor Vector Control MOTOROLA

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Motorola DSP Advantages and Features

The PWM has the following features:

• Three complementary PWM signal pairs, or 6 independent PWM signals
• Features of complementary channel operation
• Deadtime insertion
• Separate top and bottom pulse width correction via current status inputs or software
• Separate top and bottom polarity control
• Edge-aligned or center-aligned PWM signals
• 15 bits of resolution
• Half-cycle reload capability
• Integral reload rates from 1 to 16
• Individual software-controlled PWM outputs
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• Mask and swap of PWM outputs

• Programmable fault protection
• Polarity control
• 20mA current sink capability on PWM pins
• Write-protectable registers
The PM synchronous motor control utilizes the PWM block set in the complementary PWM mode,
permitting generation of control signals for all switches of the power stage with inserted deadtime. The
PWM block generates three sinewave outputs mutually shifted by 120 degrees.
The Analog-to-Digital Converter (ADC) consists of a digital control module and two analog sample
and hold (S/H) circuits. ADC features:
• 12-bit resolution
• Maximum ADC clock frequency is 5MHz with 200ns period
• Single conversion time of 8.5 ADC clock cycles (8.5 x 200 ns = 1.7µs)
• Additional conversion time of 6 ADC clock cycles (6 x 200 ns = 1.2µs)
• Eight conversions in 26.5 ADC clock cycles (26.5 x 200 ns = 5.3µs) using simultaneous mode
• ADC can be synchronized to the PWM via the sync signal
• Simultaneous or sequential sampling
• Internal multiplexer to select 2 of 8 inputs
• Ability to sequentially scan and store up to 8 measurements
• Ability to simultaneously sample and hold 2 inputs
• Optional interrupts at end of scan, if an out-of-range limit is exceeded, or at zero crossing
• Optional sample correction by subtracting a preprogrammed offset value
• Signed or unsigned result
• Single-ended or differential inputs
The application utilizes the ADC block in simultaneous mode and sequential scan. It is synchronized
with PWM pulses. This configuration allows the simultaneous conversion within the required time of
required analog values, of all phase currents, voltage and temperature.
The Quadrature Timer is an extremely flexible module, providing all required services relating to time
events. It has the following features:

MOTOROLA 3-Phase PM Synchronous Motor Vector Control 3

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Target Motor Theory

• Each timer module consists of four 16-bit counters/timers

• Count up/down
• Counters are cascadable
• Programmable count modulo
• Maximum count rate equals peripheral clock/2 when counting external events
• Maximum count rate equals peripheral clock when using internal clocks
• Count once or repeatedly
• Counters are preloadable
• Counters can share available input pins
• Each counter has a separate prescaler
• Each counter has capture and compare capability
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The PM synchronous motor vector control application utilizes four channels of the Quadrature Timer
module for position and speed sensing. A fifth channel of the Quadrature Timer module is set to
generate a time base for speed sensing and a speed controller.
The Quadrature Decoder is a module providing decoding of position signals from a Quadrature
Encoder mounted on a motor shaft. It has the following features:
• Includes logic to decode quadrature signals
• Configurable digital filter for inputs
• 32-bit position counter
• 16-bit position difference counter
• Maximum count frequency equals the peripheral clock rate
• Position counter can be initialized by software or external events
• Preloadable 16-bit revolution counter
• Inputs can be connected to a general purpose timer to aid low speed velocity.
The PM synchronous motor vector control application utilizes the Quadrature Decoder connected to Quad
Timer module A. It uses the decoder’s digital input filter to filter the encoder’s signals, but does not make
use of its decoding functions, freeing the decoder’s digital processing capabilities to be used by another
application.

3. Target Motor Theory

3.1 Permanent Magnet Synchronous Motor
The PM synchronous motor is a rotating electric machine with a classic 3-phase stator like that of an
induction motor; the rotor has surface-mounted permanent magnets (see Figure 3-1).

4 3-Phase PM Synchronous Motor Vector Control MOTOROLA

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Target Motor Theory

Stator

Stator winding
(in slots)

Shaft

Rotor

Air gap
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Permanent magnets

Figure 3-1. PM Synchronous Motor - Cross Section

In this respect, the PM synchronous motor is equivalent to an induction motor, where the air gap
magnetic field is produced by a permanent magnet, so the rotor magnetic field is constant. PM
synchronous motors offer a number of advantages in designing modern motion control systems. The
use of a permanent magnet to generate substantial air gap magnetic flux makes it possible to design
highly efficient PM motors.

3.2 Mathematical Description of PM Synchronous Motor

The model used for vector control design can be understood by using space vector theory. The
three-phase motor quantities (such as voltages, currents, magnetic flux, etc.) are expressed in terms of
complex space vectors. Such a model is valid for any instantaneous variation of voltage and current
and adequately describes the performance of the machine under both steady-state and transient
operation. The complex space vectors can be described using only two orthogonal axes. We can look
at the motor as a two-phase machine. Using a two-phase motor model reduces the number of equations
and simplifies the control design.

3.2.1 Space Vector Definition

Assume isa, isb, isc are the instantaneous balanced three-phase stator currents:
i sa + i sb + i sc = 0 (EQ 3-1.)

Then we can define the stator current space vector as follows:

2
i s = k ( i sa + ai sb + a i sc ) (EQ 3-2.)

where a and a2 are the spatial operators, a = e

j2π/3, a2 = ej4π/3 and k is the transformation constant,
chosen as k=2/3. Figure 3-2 shows the stator current space vector projection:

MOTOROLA 3-Phase PM Synchronous Motor Vector Control 5

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Target Motor Theory

β
phase- b

is β
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Figure 3-2. Stator Current Space Vector and Its Projection

The space vector defined by (EQ 3-2.) can be expressed utilizing two-axis theory. The real part of the
space vector is equal to the instantaneous value of the direct-axis stator current component, isα, and
whose imaginary part is equal to the quadrature-axis stator current component, isβ. Thus, the stator
current space vector, in the stationary reference frame attached to the stator can be expressed as:

i s = i sα + ji sβ (EQ 3-3.)

In symmetrical three-phase machines, the direct and quadrature axis stator currents isα, isβ are fictitious
quadrature-phase (two-phase) current components, which are related to the actual three-phase stator
currents as follows:

i sα = k  i sa – --- i sb – --- i sc

1 1
(EQ 3-4.)
2 2

3
i sβ = k ------- ( i sb – i sc ) (EQ 3-5.)
2
where k=2/3 is a transformation constant.
The space vectors of other motor quantities (voltages, currents, magnetic fluxes etc.) can be defined in
the same way as the stator current space vector.

6 3-Phase PM Synchronous Motor Vector Control MOTOROLA

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Target Motor Theory

For a description of the PM synchronous motor, the symmetrical three-phase smooth-air-gap machine
with sinusoidally-distributed windings is considered. The voltage equations of stator in the
instantaneous form can then be expressed as:
d
u SA = R S i SA + ψ (EQ 3-6.)
d t SA

d
u SB = R S i SB + ψ (EQ 3-7.)
d t SB

d
u SC = R S i SC + ψ (EQ 3-8.)
d t SC
where uSA, uSB and uSC are the instantaneous values of stator voltages, iSA, iSB and iSC are the
instantaneous values of stator currents, and ψSA, ψSB, ψSC are instantaneous values of stator flux
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linkages, in phase SA, SB and SC.

Due to the large number of equations in the instantaneous form, the equations (EQ 3-6.), (EQ 3-7.)
and (EQ 3-8.), it is more practical to rewrite the instantaneous equations using two axis theory (Clarke
transformation). The PM synchronous motor can be expressed as:
d
uSα = R S i Sα + Ψ (EQ 3-9.)
d t Sα

d
u Sβ = R S i Sβ + Ψ (EQ 3-10.)
d t Sβ

Ψ Sα = L S i Sα + Ψ M cos ( Θ r ) (EQ 3-11.)

Ψ Sβ = L S i Sβ + Ψ M sin ( Θ r ) (EQ 3-12.)

dω p 3
= --- --- p ( Ψ Sα i Sβ – Ψ Sβ i Sα ) – T L (EQ 3-13.)
dt J 2
where: α,β is the stator orthogonal coordinate system
uSα,β is the stator voltage
iSα,β is the stator current
ΨSα,β is the stator magnetic flux
ΨM is the rotor magnetic flux
RS is the stator phase resistance
LS is the stator phase inductance
ω / ωF is the electrical rotor speed / fields speed
p is the number of poles per phase
J is the inertia
TL is the load torque
Θr is the rotor position in α,β coordinate system

The equations (EQ 3-9.) through (EQ 3-13.) represent the model of PM synchronous motor in the
stationary frame α, β fixed to the stator.

MOTOROLA 3-Phase PM Synchronous Motor Vector Control 7

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Target Motor Theory

Besides the stationary reference frame attached to the stator, motor model voltage space vector
equations can be formulated in a general reference frame, which rotates at a general speed ωg. If a
general reference frame is used, with direct and quadrature axes x,y rotating at a general instantaneous
speed ωg=dθg/dt, as shown in Figure 3-3, where θg is the angle between the direct axis of the
stationary reference frame (α) attached to the stator and the real axis (x) of the general reference frame,
then (EQ 3-14.) defines the stator current space vector in general reference frame:
– jθg
i sg = i s e = i sx + ji sy (EQ 3-14.)

y β
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Figure 3-3. Application of the General Reference Frame

The stator voltage and flux-linkage space vectors can be similarly obtained in the general reference
frame.
Similar considerations hold for the space vectors of the rotor voltages, currents and flux linkages. The
real axis (rα) of the reference frame attached to the rotor is displaced from the direct axis of the stator
reference frame by the rotor angle θr. Since it can be seen that the angle between the real axis (x) of the
general reference frame and the real axis of the reference frame rotating with the rotor (rα) is θg-θr, in
the general reference frame, the space vector of the rotor currents can be expressed as:
–j ( θg – θr )
i rg = i r e = i rx + ji ry (EQ 3-15.)

where i r is the space vector of the rotor current in the rotor reference frame.
The space vectors of the rotor voltages and rotor flux linkages in the general reference frame can be
similarly expressed.
The motor model voltage equations in the general reference frame can be expressed by utilizing
introduced transformations of the motor quantities from one reference frame to the general reference
frame. The PM synchronous motor model is often used in vector control algorithms. The aim of vector
control is to implement control schemes which produce high dynamic performance and are similar to
those used to control DC machines. To achieve this, the reference frames may be aligned with the

8 3-Phase PM Synchronous Motor Vector Control MOTOROLA

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Target Motor Theory

stator flux-linkage space vector, the rotor flux-linkage space vector or the magnetizing space vector.
The most popular reference frame is the reference frame attached to the rotor flux linkage space vector,
with direct axis (d) and quadrature axis (q).
After transformation into d-q coordinates, the motor model as follows:
d
u Sd = RS i Sd + Ψ – ω F Ψ Sq (EQ 3-16.)
d t Sd
d
u Sq = R S i Sq + Ψ + ω F Ψ Sd (EQ 3-17.)
d t Sq

Ψ Sd = L S i Sd + Ψ M (EQ 3-18.)

Ψ Sq = L S i Sq (EQ 3-19.)
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dω p 3
= --- --- p ( Ψ Sd i Sq – Ψ Sq i Sd ) – T L (EQ 3-20.)
dt J 2
By considering that below base speed isd=0, the equation (EQ 3-20.) can be reduced to the following
form:

dω p 3
= --- --- p ( Ψ M i Sq ) – T L (EQ 3-21.)
dt J 2
From the equation (EQ 3-21.), it can be seen that the torque is dependent and can be directly controlled
by the current isq only.

3.3 Digital Control of PM Synchronous Motor

In adjustable-speed applications, the PM synchronous motors are powered by inverters. The inverter
converts DC power to AC power at the required frequency and amplitude. The typical 3-phase inverter
is illustrated in Figure 3-4.

U DCB

Q1 Q3 Q5

PWM_Q1 PWM_Q3 PWM_Q5

C1

Q2 Q4 Q6

PWM_Q2 PWM_Q4 PWM_Q6

GND
Phase_A Phase_B Phase_C

Figure 3-4. 3- Phase Inverter

MOTOROLA 3-Phase PM Synchronous Motor Vector Control 9

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Target Motor Theory

The inverter consists of three half-bridge units where the upper and lower switches are controlled
complementarily, meaning when the upper one is turned on, the lower one must be turned off, and vice
versa. Because the power device’s turn off time is longer than its turn on time, some deadtime must be
inserted between the turn off of one transistor of the half-bridge, and the turn on of its complementary
device. The output voltage is mostly created by a pulse width modulation (PWM) technique, where an
isosceles triangle carrier wave is compared with a fundamental-frequency sine modulating wave, and
the natural points of intersection determine the switching points of the power devices of a half bridge
inverter. This technique is shown in Figure 3-5. The 3-phase voltage waves are shifted 120o to each
other and, thus, a 3-phase motor can be supplied.

Generated P WM Carrier
S ine Wave Wave
1
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0
ωt

-1

1
P WM Output T
1 0
(U pper S witch)
ωt
1
P WM Output T
2 0
(L ower S witch)
ωt

Figure 3-5. Pulse Width Modulation

The most popular power devices for motor control applications are Power MOSFETs and IGBTs.
A Power MOSFET is a voltage-controlled transistor. It is designed for high-frequency operation and
has a low voltage drop; thus, it has low power losses. However, the saturation temperature sensitivity
limits the MOSFET application in high-power applications.
An insulated-gate bipolar transistor (IGBT) is a bipolar transistor controlled by a MOSFET on its base.
The IGBT requires low drive current, has fast switching time, and is suitable for high switching
frequencies. The disadvantage is the higher voltage drop of a bipolar transistor, causing higher
conduction losses.

3.3.1 Vector Control of PM Synchronous Motor

Vector Control is an elegant control method of a PM synchronous motor, where field-oriented theory
is used to control space vectors of magnetic flux, current, and voltage. It is possible to set up the
coordinate system to decompose the vectors into a magnetic field-generating part and a
torque-generating part. The structure of the motor controller (Vector Control controller) is then almost
the same as for a separately-excited DC motor, which simplifies the control of PM synchronous motor.
This Vector Control technique was developed specifically to achieve a similarly dynamic performance
in PM synchronous motors.
As explained in Section 4.2, we chose a widely used speed control with inner current closed-loop,
where the rotor flux is controlled by a field-weakening controller.

10 3-Phase PM Synchronous Motor Vector Control MOTOROLA

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Target Motor Theory

In this method, we must break down the field-generating and torque-generating parts of the stator
current to be able to separately control the magnetic flux and the torque. In order to do so, we need to
set up the rotary coordinate system connected to the rotor magnetic field; this system is generally
called a “d-q coordinate system”. Very high CPU performance is needed to perform the transformation
from rotary to stationary coordinate systems. Therefore, the Motorola DSP56F80x is very well suited
for use in a Vector Control algorithm. All transformations which are needed for Vector Control will be
described in the next section.

3.3.2 Block Diagram of Vector Control

Figure 3-6 shows the basic structure of Vector Control of the PM synchronous motor. To perform
Vector Control, follow these steps:
• Measure the motor quantities (phase voltages and currents)
• Transform them into the two-phase system (α,β) using Clarke transformation
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• Calculate the rotor flux space vector magnitude and position angle
• Transform stator currents into the d-q coordinate system using Park transformation
• The stator current torque- (isq) and flux- (isd) producing components are controlled separately
by the controllers
• The output stator voltage space vector is calculated using the decoupling block
• The stator voltage space vector is transformed back from the d-q coordinate system into the
two-phase system and fixed with the stator by inverse Park transformation
• Using sinewave modulation, the output 3-phase voltage is generated

Speed Line Input

ommand USq_lin

- - USd USα
Decoupling

Sinewave
USq
Generation
USβ

USd_lin

pwm a
pwm b
3-phase Power Stage
pwm c
USd USq
ISq
ISα ISa

ISb
Forward Park Forward Clarke
ISd
Transformation ISβ Transformation ISc

PMSM
motor

Speed Position
Position/Speed
sensor

Figure 3-6. Block Diagram of PM Synchronous Motor Vector Control

MOTOROLA 3-Phase PM Synchronous Motor Vector Control 11

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Target Motor Theory

3.3.3 Vector Control Transformations

Transforming the PM synchronous motor into a DC motor is based on points of view. As shown in
Section 3.3.2, a coordinate transformation is required.
The following transformations are involved in Vector Control:
• Transformations from a 3-phase to a 2-phase system (Clarke transformation)
• Rotation of orthogonal system
— α,β to d-q (Park transformation)
— d-q to α,β (Inverse Park transformation)

3.3.3.1 Clarke Transformation

Figure 3-7. shows how the three-phase system is transformed into a two-phase system.
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β
phase- b

iS
iSE
iSb - measured iSa - measured
iSD α, phase-a

iSc - calculated

phase- c
Figure 3-7. Clarke Transformation

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Target Motor Theory

To transfer the graphical representation into mathematical language:

1 1
1 – --- – --- a
α = K 2 2
(EQ 3-22.)
b
β 3 3
0 ------- – ------- c
2 2
In most cases, the 3-phase system is symmetrical, which means that the sum of the phase quantities is
always zero.

α = K  a – --- b – --- c =

1 1 3
a+b+c = 0 = K --- a (EQ 3-23.)
2 2 2
The constant “K” can be freely chosen and equalizing the α-quantity and a-phase quantity is
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recommended. Then:
2
α = a ⇒ K = --- (EQ 3-24.)
3
We can fully define the Park-Clarke transformation:

2--- 1 1
– --- – --- a 1 0 0 a
α = 3 3 3
b = a+b+c = 0 = 1- 1 b (EQ 3-25.)
β 0
1 1
------- – ------- c
0 ------ – -------
3 3 c
3 3

3.3.3.2 Transformation from α,β to d-q Coordinates and Backwards

Vector Control is performed entirely in the d-q coordinate system to make the control of PM
synchronous motors elegant and easy; see Section 3.3.2.
Of course, this requires transformation in both directions and the control action must be transformed
back to the motor side.
First, establish the d-q coordinate system:

ΨM = Ψ Mα + Ψ Mβ (EQ 3-26.)

Ψ Mβ
sin ϑ Field = -----------
Ψ Md
(EQ 3-27.)
Ψ Mα
cos ϑ Field = -----------
Ψ Md

Then transform from α,β to d-q coordinates:

d = cos ϑField sin ϑ Field α (EQ 3-28.)

q – sin ϑ Field cos ϑ Field β

MOTOROLA 3-Phase PM Synchronous Motor Vector Control 13

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Target Motor Theory

Figure 3-8. illustrates this transformation.

q β

ΨM d

ΨMβ ϑField
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α
ΨMα
Figure 3-8. Establishing the d-q Coordinate System (Park Transformation)

The backward (Inverse Park) transformation (from d-q to α,β) is:

α = cos ϑ Field – sin ϑ Field d

(EQ 3-29.)
β sin ϑ Field cos ϑ Field q

3.3.4 PMSM Vector Control and Field-Weakening Controller

This section describes the control regarding the required stator current vectors isd, isq.
There are two speed ranges (shown in Figure 3-9), which differ by controlled current vector:
• Control in Normal Operating Range is a control mode for a speed required below nominal
motor speed
• Control in Field-Weakening Range is a control mode for a speed required above nominal
motor speed

3.3.4.1 Control in Normal Operating Range

Assume an ideal PM synchronous motor with constant stator reluctance, Ls = const. The equations
(EQ 3-17.), (EQ 3-18.) and (EQ 3-19.) can then be written as:
d
u Sq = R S i Sq + L S i Sq + ω F ( L S i Sd + Ψ M ) (EQ 3-30.)
dt

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Target Motor Theory

As demonstrated from PM synchronous motor equations, the maximum efficiency of the ideal PM
synchronous motor is obtained when maintaining the current flux-producing component isd at zero.
Therefore, in the drive from Figure 3-6, the Field-Weakening Controller sets isd = 0 in the normal
operating range. The speed regulator controls the current torque-producing component isq.
A real 3-phase power inverter has voltage and current rating limitations:
1. The absolute value of stator voltage us is physically limited according to DCBus voltage to
u_sdq_max limit
2. The absolute value of the stator current is should be maintained below a limit of I_SDQ_MAX
given by the maximum current rating
In the normal operating range, the current torque-producing component isq can be set up to
I_SDQ_MAX, since isd = 0.
Due to the voltage limitation, the maximum speed in the normal motor operating range is limited for
Freescale Semiconductor, Inc...

isd = 0, to a nominal motor speed as shown in Figure 3-9 and (EQ 3-30.).

nominal speed
stator voltage us
u_sdq_max

normal operating field weakenning speed

0 range range

stator current id

Figure 3-9. Normal Operation and Field-Weakening

3.3.4.2 Control in Field-Weakening Range

Where a higher maximum motor speed is required, the field-weakening technique must be used. That
is provided by maintaining the flux-producing current component isd, in the field-weakening range, as
shown in Figure 3-9.
Due to the limitation of absolute current value, the current torque-producing component isq, then must
be maintained below a limited value.

2 2
i Sq < I_SDQ_MAX – i Sd (EQ 3-31.)

One possibility to maintain the flux-producing current component isd for field weakening is to use a
look-up table.

MOTOROLA 3-Phase PM Synchronous Motor Vector Control 15

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System Concept

A more-progressive method uses a Field-Weakening Controller, which generates a negative current

flux-producing component isq, whenever the absolute value of stator voltage exceeds
u_S_max_FWLimit. The field-weakening limit u_S_max_FWLimit is set to be close to the maximum
voltage limit of the 3-phase power inverter u_sdq_max with some reserve for regulation. Since the
DCBus voltage determines the u_sdq_max limit, the u_S_max_FWLimit is set according to the
DCBus. The u_S_max_FWLimit can be a constant or it can be calculated from a measured DCBus
voltage. The Field-Weakening controller is described in Section 6.2.5.4.

4. System Concept
4.1 System Specification
The motor control system is designed to drive a 3-phase PM synchronous motor in a speed
closed-loop. The application meets the following performance specifications:
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• Vector control of PM motor using the quadrature encoder as a position sensor

• Targeted for DSP56F80xEVM
• Running on a 3-phase PM synchronous motor control development platform at variable line
voltage 110 - 230V AC
• Control technique incorporates:
— Vector Control with speed closed-loop and field-weakening
— Rotation in both directions
— Motoring and generator mode with brake
— Start from any motor position with rotor alignment
— Minimum speed of 50rpm
— Maximum speed of 3000rpm at input power line 230V AC
— Maximal speed of 1500rpm at input power line 115V AC
• Manual interface (Start/Stop switch, Up/Down push button control, LED indicator)
• PC master software control interface (motor start/stop, speed set-up)
• PC master software remote monitor
• Power stage board identification
• Overvoltage, undervoltage, overcurrent and overheating fault protection
The PM synchronous drive introduced here is designed to power a high-voltage PM synchronous
motor with a quadrature encoder. It has the following specifications:

Table 1: High Voltage Hardware Set Specifications

Motor Characteristics: Motor Type 6 poles, 3-phase, star connected,
BLDC motor

Speed Range 2500rpm (at 310V DCBus)

Maximum Electrical Power: 150 W

Phase Voltage 3*220V

Phase Current 0.55A

16 3-Phase PM Synchronous Motor Vector Control MOTOROLA

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System Concept

Table 1: High Voltage Hardware Set Specifications (Continued)

Drive Characteristics: Speed Range < 3000rpm

Input Voltage 310V DC

Maximum DCBus Voltage 380V

Control Algorithm Speed Closed-Loop Control

Optoisolation Required

4.2 Vector Control Drive Concept

A standard system concept is used with this drive; see Figure 4-1. The system incorporates the
following hardware parts:
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• Three-phase PM synchronous motor high-voltage development platform

• Feedback sensors for:
— Position (quadrature encoder)
— DCBus voltage
— Phase currents
— DCBus overcurrent detection
— Temperature
• Three DSP56F80x Evaluation Modules:
— DSP56F803EVM
— DSP56F805EVM
— DSP56F807EVM
The drive can be controlled in two different operational modes:
In the Manual operational mode, the required speed is set by the Start/Stop switch and the Up/Down
push buttons.
In the PC master software operational mode, the required speed and Start/Stop switch are set by the
PC.

MOTOROLA 3-Phase PM Synchronous Motor Vector Control 17

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System Concept

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Figure 4-1. Drive Concept

The control process is as follows:

When the Start command is accepted (using the Start/Stop Switch or PC master software command),
the required speed is calculated according to the Up/Down push buttons or PC master software
commands. The required speed proceeds through an acceleration/deceleration ramp, and a reference
command is put to the speed controller. The actual speed is calculated from the pulses of the
quadrature encoder. The comparison between the required speed command and the actual measured
speed generates a speed error. Based on the error, the speed controller generates a current, Is_qReq,
which corresponds to torque. A second part of stator current Is_dReq, which corresponds to flux, is
given by the Field-Weakening Controller. Simultaneously, the stator currents Is_a, Is_b, and Is_c are
measured and transformed from instantaneous values into the stationary reference frame α, β, and
consecutively into the rotary reference frame d-q (Park - Clarke transformation). Based on the errors
between required and actual currents in the rotary reference frame, the current controllers generate
output voltages Us_q and Us_d (in the rotary reference frame d-q). The voltages Us_q and Us_d are
transformed back into the stationary reference frame α, β and, after DCBus ripple elimination, are
recalculated to the 3-phase voltage system, which is applied to the motor.
Beside the main control loop, the DCBus voltage, DCBus current and power stage temperature are
measured during the control process. They are used for overvoltage, undervoltage, overcurrent and
overheating protection of the drive. The undervoltage and overheating protection is performed by
software, while the overcurrent and overvoltage fault signal utilizes a fault input of the DSP.

18 3-Phase PM Synchronous Motor Vector Control MOTOROLA

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If any of the previously-mentioned faults occur, the motor control PWM outputs are disabled in order
to protect the drive, and the fault state of the system is displayed by the on-board LED.
A hardware error is also detected if the wrong power stage is used. Each power stage contains a simple
module generating a logic sequence unique for that type of power stage. During chip initialization, this
sequence is read and evaluated according to the decoding table. If the correct power stage is identified,
the program can continue. In the case of wrong hardware, the program stays in an infinite loop,
displaying the fault condition.

4.3 System Blocks Concept

4.3.1 Position and Speed Sensing
All members of Motorola’s DSP56F80x family, except the DSP56F801 device , have a quadrature
decoder. This peripheral is commonly used for position and speed sensing. The quadrature decoder
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position counter counts up/down each edge of Phase A and Phase B signals according to their order.
On each revolution, the position counter is cleared by an index pulse; see Figure 4-2.

Figure 4-2. Quadrature Encoder Signals

This means that the zero position is linked with the index pulse, but Vector Control requires the zero
position, where the rotor is aligned to the d axis; see Section 4.3.1.3. Therefore, using a quadrature
decoder to decode the encoder’s signal requires either the calculation of an offset which aligns the
quadrature decoder position counter with the aligned rotor position (zero position), or the coupling of
the zero rotor position with the index pulse of a quadrature encoder. To avoid the calculation of the
rotor position offset, the quadrature decoder is not used in this application. The decoder’s digital
processing capabilities are then free to be used by another application and the application presented can
then run on the DSP56F801, which lacks a quadrature decoder.
In addition to the quadrature decoder, the input signals (Phase A, Phase B and Index) are connected to
quad timer module A. The quad timer module consists of four quadrature timers. Due to the wide
variability of quad timer modules, it is possible to use this module to decode quadrature encoder
signals, sense position, and speed. A configuration of the quad timer module is shown in Figure 4-3.

MOTOROLA 3-Phase PM Synchronous Motor Vector Control 19

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Figure 4-3. Quad Timer Module A Configuration

4.3.1.1 Position Sensing

The position and speed sensing algorithm uses all of the timers in module A and an additional timer as
a time base. Timers A0 and A1 are used for position sensing. Timer A0 permits connection of three
input signals to the quadrature timer A1, even if timer A1 has only two inputs (primary and
secondary), accomplished by using timer A0 as a quadrature decoder only. It is set to count in the
quadrature mode, count to zero, and then reinitialize. This timer setting is used to decode quadrature
signals only. Timer A1 is connected to timer A0 in cascade mode. In this mode, the information about
counting up/down is connected internally to timer A1; thus, the secondary input of timer A1 is free to
be used for the index pulse. The counter A1 is set to count to +/- ((4*number of pulses per revolution)
- 1) and reinitialize after compare. The value of the timer A1 corresponds to the rotor position.
The position of the index pulse is sensed to avoid the loss of some pulses under the influence of noise
during extended motor operation, which can result in incorrect rotor position sensing. If some pulses
are lost, a different position of the index pulse is detected, and a position sensing error is signaled. If a
check of the index pulse is not required, timer A1 can be removed and timer A0 set as the position
counter A1. The resulting value of timer A1 is scaled to range <-1; 1), which corresponds to <-π; π).

4.3.1.2 Speed Sensing

There are two common ways to measure speed. The first method measures the time between two
following edges of quadrature encoder, and the second method measures a position difference (a
number of pulses) per constant period. The first method is used at low speed. At the moment when the
measured period is very short, the speed calculation algorithm switches to the second method.

20 3-Phase PM Synchronous Motor Vector Control MOTOROLA

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System Concept

The proposed algorithm combines both methods. The algorithm simultaneously measures the number
of quadrature encoder pulses per constant period, and an accurate time interval between the first and
last pulse is counted during that constant period. The speed can then be expressed as:
k⋅N
speed = -----------
T
(EQ 4-1.)
where:
speed calculated speed
k scaling constant
N number of pulses per constant period
T accurate period of N pulses
The algorithm requires two timers for counting pulses and measuring their period, and a third timer as
Freescale Semiconductor, Inc...

a time base; see Figure 4-3. Timer A2 counts the pulses of the quadrature encoder, and timer A3
counts a system clock divided by 2. The values in both timers can be captured by each edge of the
Phase A signal. The time base is provided by timer D0, which is set to call the speed processing
algorithm every 900µs. An explanation of how the speed processing algorithm works follows.
First, the new captured values of both timers are read. The difference in the number of pulses and their
accurate time interval are calculated from actual and previous values. The new values are then saved
for the next period, and the capture register is enabled. From that moment, the first edge of Phase A
signal captures the values of both timers (A2, A3) and the capture register is disabled. This process is
repeated on each call of the speed processing algorithm; see Figure 4-4.

Figure 4-4. Speed Processing

MOTOROLA 3-Phase PM Synchronous Motor Vector Control 21

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System Concept

4.3.1.2.1 Minimum and Maximum Speed Calculation

The minimum speed is calculated with the following equation:

60
ω min = ------------------- (EQ 4-1.)
4NT calc

where:
ωmin Minimum obtainable speed [rpm]
N Number of pulses per revolution [1/rev]
Tcalc Period of speed measurement (calculation period) [s]
In the application, the quadrature encoder has 1024 pulses per revolution and a calculation period of
900µs was chosen on the basis of a motor mechanical constant. Thus, (EQ 4-1.) calculates the
Freescale Semiconductor, Inc...

minimum speed as 16.3 rpm.

The maximum speed can be expressed as:

60
ω max = ----------------------
4NTclkT2 (EQ 4-2.)

where:
ωmax Maximum obtainable speed [rpm]
N Number of pulses per revolution [1/rev]
TclkT2 Period of input clock to timer A2 [s]
Substitution in (EQ 4-2.) for N and TclkT2 (timer A2 input clock = system clock 36 MHz/2) yields a
maximum speed of 263672rpm. As demonstrated, the algorithm can measure speed across a wide
range. Because such high speed is not practical, the maximum speed can be reduced to a required
range by the constant k in (EQ 4-1.). The constant k can be calculated as:

60
k = -----------------------------------
4NT clkT2 ω max (EQ 4-3.)

where:
k Scaling constant in (EQ 4-1.)
ωmax Maximum of the speed range [rpm]
N Number of pulses per revolution [1/rev]
TclkT2 Period of input clock to timer A2 [s]
In this application, the maximum measurable speed is limited to 6000rpm.

Note: To ensure an accurate speed calculation, you must choose the input clock of timer A2 so that
the calculation period of speed processing (in this case, 900µs) is represented in timer A2 as a
value lower than 0x7FFFH (900.10-6/TclkT2<=0x7FFFH).

22 3-Phase PM Synchronous Motor Vector Control MOTOROLA

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4.3.1.3 Position Reset with Rotor Alignment

After reset, the rotor position is unknown, because a quadrature encoder does not give an absolute
position until the index pulse arrives. As shown in Figure 4-5, the rotor position must be aligned with
the d axis of the d-q coordinate system before a motor begins running. The alignment algorithm is
shown in Figure 4-6. First, the position is set to zero, independent of the actual rotor position. (The
value of the quadrature encoder does not affect this setting). Then the Id current is set to alignment
current. The rotor is now aligned to the required position. After rotor stabilization, the encoder is reset
to the zero position, then the Id current is set back to zero, and alignment is finished. The alignment is
executed only once during the first transition from the Stop to Run state of the Run/Stop switch.

β
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q unknown rotor position

(not aligned)

zero rotor position

(aligned)
ΨM ϑField = 0

d α
Figure 4-5. Rotor Alignment

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Figure 4-6. Rotor Alignment Flow Chart

MOTOROLA 3-Phase PM Synchronous Motor Vector Control 23

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System Concept

4.3.2 Current Sensing

Phase currents are measured by a shunt resistor in each phase. A voltage drop on the shunt resistor is
amplified by an operational amplifier, and shifted up by 1.65V. The resultant voltage is converted by
an A/D converter (see Figure 4-7 and Figure 4-8).

Q1 Q3 Q5
SKB04N60 SKB04N60 SKB04N60

Gate_AT Gate_BT Gate_CT

Phase_A Phase_B Phase_C

Q2 Q4 Q6
SKB04N60 SKB04N60 SKB04N60

Gate_AB Gate_BB Gate_CB

Source_AB Source_BB Source_CB

Freescale Semiconductor, Inc...

I_sense_A1 sense R1 I_sense_B1 sense R2 I_sense_C1 sense R3

0.1 1% 0.1 1% 0.1 1%

I_sense_A2 sense I_sense_B2 sense I_sense_C2 sense

Figure 4-7. Current Shunt Resistors

R318 75k-1%

R320 10k-1%
6 1.65V +/- 1.65V @ +/- Imax
I_sense_C1 -
7
I_sense_C
I_sense_C2 5 +

R321 10k-1%
R322 U301B
R323 390 75k-1% MC33502D
1.65V ref
+3.3V_A
+
R324
8

C307 C306 100k-1%

100nF 3.3uF/10V 5

LM285M R325
U304 33k-1%
GNDA
4

GNDA

Figure 4-8. Current Amplifier

As shown in Figure 4-7, the currents cannot be measured at any moment. For example, the current
flows through Phase A (and shunt resistor R1) only if transistor Q2 is switched on. Likewise, the
current in Phase B can be measured if transistor Q4 is switched on, and the current in Phase C can be
measured if transistor Q6 is switched on. To get a moment of current sensing, a voltage shape analysis
must be done.
The voltage shapes of two different PWM periods are shown in Figure 4-11. The voltage shapes
correspond to center-aligned PWM sinewave modulation. As shown, the best moment of current
sampling is in the middle of the PWM period, where all bottom transistors are switched on.
To set the exact moment of sampling, the DSP56F80x family offers the ability to synchronize ADC
and PWM modules via the SYNC signal. This exceptional hardware feature, patented by Motorola, is
used for current sensing. The PWM outputs a synchronization pulse, which is connected as an input to

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System Concept

the synchronization module TC2 (Quad Timer C, counter/timer 2). A high-true pulse occurs for each
reload of the PWM, regardless of the state of the LDOK bit. The intended purpose of TC2 is to provide
a user-selectable delay between the PWM SYNC signal and the updating of the ADC values. A
conversion process can be initiated by the SYNC input, which is an output of TC2. The time diagram
of the automatic synchronization between PWM and ADC is shown in Figure 4-9.

PWM COUNTER
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PWM SYNC

PWM
GENERATOR
OUTPUTS 0, 1
dead-time/2 dead-time/2

PWM
PINS 0, 1

POWER
STAGE dead-time dead-time
VOLTAGE

TC2
COUNTER
t1
TC2
OUTPUT
t2
ADC
CONVERSION

ADC
ISR

Figure 4-9. Time Diagram of PWM and ADC Synchronization

However, all three currents cannot be measured from one voltage shape. The PWM period II in
Figure 4-11 shows a moment when the bottom transistor of Phase A is switched on for a very short
time. If the on-time is shorter than a critical time, the current can not be accurately measured. The
critical time is given by hardware configuration (transistor commutation times, response delays of the
processing electronics, etc.). Therefore, only two currents are measured and a third current is
calculated from the following equation:

0 = i A + iB + iC (EQ 4-4.)

MOTOROLA 3-Phase PM Synchronous Motor Vector Control 25

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System Concept

I. II.
PWM PERIOD PWM RELOAD

PHASE_A

PHASE_B

PHASE_C

critical pulse width

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ADC sampling point

Figure 4-10. Voltage Shapes of Two Different PWM Periods

II. I.



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Figure 4-11. 3-phase Sinewave Voltages and Corresponding Sector Value

A decision must now be made about which phase current should be calculated. The simplest technique
is to calculate the current of the most positive voltage phase. For example, Phase A generates the most
positive voltage within section 0 - 60ƒ3KDVH%ZLWKLQVHFWLRQƒƒDQGVRRQVHHFigure 4-11.
In this case, the output voltages are divided into six sectors, as shown in Figure 4-11. The current
calculation is then made according to the actual sector value.
Sectors 1 and 6:

i A = – iB – i C (EQ 4-5.)

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Sectors 2 and 3:

i B = – iA – iC (EQ 4-6.)

Sectors 4 and 5:

i C = – iB – i A (EQ 4-7.)

Note: The sector value is used for current calculation only, and has no other meaning in the sinewave
modulation. But if we use any type of space vector modulation, we can get the sector value as
part of space vector calculation.

4.3.3 Voltage Sensing

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The DCBus voltage sensor is represented by a simple voltage divider. The DCBus voltage does not
change rapidly. It is nearly constant, with the ripple given by the power supply structure. If a bridge
rectifier is used for rectification of the AC line voltage, the ripple frequency is twice the AC line
frequency. If the power stage is designed correctly, the ripple amplitude should not exceed 10% of the
nominal DCBus value.
The measured DCBus voltage must be filtered to eliminate noise. One of the easiest and fastest
techniques is the first order filter, which calculates the average filtered value recursively from the last
two samples and coefficient C:

u DCBusFilt ( n + 1 ) = ( Cu DCBusFilt ( n + 1 ) – Cu DCBusFilt ( n ) ) – uDCBusFilt ( n ) (EQ 4-8.)

To speed up the initialization of the voltage sensing (the filter has exponential dependency with
constant of 1/N samples), the moving average filter, which calculates the average value from the last N
samples, can be used for initialization:
–N
u DCBusFilt = ∑n = 1 uDCBus ( n ) (EQ 4-9.)

4.3.4 Power Module Temperature Sensing

The measured power module temperature is used for thermal protection The hardware realization is
shown in Figure 4-12. The circuit consists of four diodes connected in series, a bias resistor, and a
noise suppression capacitor. The four diodes have a combined temperature coefficient of 8.8 mV/οC.
The resulting signal, Temp_sense, is fed back to an A/D input, where software can be used to set safe
operating limits. In this application, the temperature, in Celsius, is calculated according to the
conversion equation:
Temp_sense – b
temp = -------------------------------------- (EQ 4-10.)
a
where:
temp Power module temperature in centigrades
Temp_sense Voltage drop on the diodes, which is measured by ADC [V]
a Diodes-dependent conversion constant (a = -0.0073738)
b Diodes-dependent conversion constant (b = 2.4596)

MOTOROLA 3-Phase PM Synchronous Motor Vector Control 27

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Hardware Implementation

+3.3V_A

R1
2.2k - 1%

Temp_sense
D1 D2
BAV99LT1 BAV99LT1 C1
100nF

Figure 4-12. Temperature Sensing

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5. Hardware Implementation
5.1 Hardware Set-up
The application can run on Motorola’s motor control DSPs using the DSP56F803EVM,
DSP56F805EVM, or DSP56F807EVM, Motorola’s 3-Phase AC/BLDC high voltage power stage and
the BLDC high voltage motor with a quadrature encoder and integrated brake. All components are an
integral part of Motorola’s embedded motion control development tools. Application hardware set-up
is shown in Figure 5-1.
The system hardware set-up for a particular DSP varies only by the EVM Board used. The application
level of the software is identical for all DSPs. The EVM and chip differences are handled by the
off-chip software drivers for the particular DSP EVM board.
Detailed application hardware set-up can be found in the Targeting Motorola DSP5680x Platform
manual.

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Hardware Implementation

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All system parts are supplied and documented in these references:

• U1 - Controller Board for the:
— DSP56F803
— Supplied as DSP56F803EVM
— Described in the DSP56F803 Evaluation Module Hardware User’s Manual
— DSP56F805
— Supplied as DSP56F805EVM
— Described in the DSP56F805 Evaluation Module Hardware User’s Manual
— DSP56F807
— Supplied as DSP56807EVM
— Described in DSP56F807Evaluation Module Hardware User’s Manual
• U2 - 3-phase AC/BLDC High-Voltage Power Stage
— Supplied in a kit with the In-Line Optoisolation Box (Order #ECINLHIVACBLDC)
— Described in the 3-phase Brushless DC High Voltage Power Stage Manual
• U3 - In-Line Optoisolation Box
— Supplied in a kit with the 3-phase AC/BLDC High Voltage Power Stage (Order
#ECINLHIVACBLDC) or solo (Order #ECOPTINL)
— Described in the In-Line Optoisolation Box Manual

WARNING: It is strongly recommended to use an In-line Optoisolation Box during

development to avoid any damage to the development equipment.

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• MB1 Motor-Brake SM40V + SG40N

— Supplied as Order #ECMTRHIVBLDC

Note: The application software is targeted for a PM synchronous motor with sinewave Back-EMF
shape. In this demo application, a BLDC motor is used instead, due to the availability of the
BLDC motor (MB1). Although the Back-EMF shape of this motor is not an ideal sinewave, it
can be controlled by the application software. The drive parameters will be ideal with a PMSM
motor with an exact sinewave Back-EMF shape.
A detailed description of the individual board can be found in the appropriate DSP56F80x Evaluation
Module User’s Manual, or on the Motorola web site, http://-www.motorola.com. The User’s
Manual includes the schematic of the board, description of individual function blocks, and a bill of
materials. The individual boards can be ordered from Motorola as standard products.

6.
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Software Design
This section describes the design of the drive’s software blocks. The software description comprises
these topics:
• Main Software Flow Chart
• Data Flow
• State Diagram
For more information on the system blocks used, refer to Section 4.3.

6.1 Main Software Flow Chart

The main software flow chart incorporates the Main routine entered from Reset (see Figure 6-1) and
Interrupt states (see Figure 6-2, Figure 6-3). The Main routine includes the initialization of the DSP
and the main loop.
The software consist of processes: Application Control, PM Synchronous Motor (PMSM) Control,
Analog sensing, Position and Speed Measurement, Fault Control, and Brake Control.
The Application Control process is the highest software level which precedes settings for other
software levels. The input of this level is the Run/Stop switch, Up/Down buttons for manual control,
and PC master software (via the registers shown in Section 6.2). This process is handled by
Application Control Processing called from Main; see Figure 6-1.
The PMSM (PM Synchronous Motor) Control process provides most of the motor control
functionality. It is split into Current Processing and Speed Processing. Current Processing is called
from ADC Complete Interrupt (see Figure 6-2) once per two PWM reloads, with a period 125µs. It
can also be set to each PWM reload (62.5µs), but the PC master software recorder
pcmasterdrvRecorder() must be removed from the code. Speed Processing is called from the
Quadrature Timer D0 Interrupt (see Figure 6-3) with the period PER_TMR_POS_SPEED_US
(900µs). The advantage of splitting the current and the speed control processes is that current control
can be executed with a high priority and frequency of calls, while the execution of the speed control is
not that highly prioritized.
The Analog sensing process handles sensing, filtering and correction of analog variables (phase
currents, temperature, DCBus voltage). It is provided by Analog Sensing Processing (see Figure 6-2)
and Analog Sensing ADC Phase Set. Analog Sensing ADC Phase Set is split from Analog Sensing
Processing because it sets ADC according to the svmSector variable, calculated after PMSM Control
Current Processing.

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Position and Speed Measurement processes are provided by hardware Timer modules and the
functions giving the actual speed and position; see Figure 4.3.1.
LED Indication Processing is called from Quadrature Timer D0 Interrupt, which provides the time
base for LED flashing.
The Fault Control process is split into Background and PWM Fault ISR. Background (see Figure 6-1)
checks the Overheating, Undervoltage and Position Sensing Faults. The PWM Fault ISR part (see
Figure 6-2) takes care of Overvoltage and Overcurrent Faults, which causes a PWM A Fault interrupt.
The Brake Control process is dedicated to the brake transistor control, which maintains the DCBus
voltage level. It is called from Main (see Figure 6-1).
The Up/Down Button and Switch Control processes are subprocesses of Application Control and are
described in Section 7.4.
The Up/Down Button processes are split into Button Processing Interrupt, called from Quadrature
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Timer D0 Interrupt (see Figure 6-3); Button Processing BackGround (inside Analog Sensing);
Interrupt Up Button; and Interrupt Down Button (see Figure 6-2).

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Reset

DSP Initialization

Fault Control - Background:

if faultCtrlStatus - AnalogFaultEnbl
{check Undervoltage, Overheating
faults}
if Position sensing,Overvoltage,
Overcurrent faults
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{set appFaultStatus
trigger beginning of Fault State}

Application Control - Processing:

according to appOpMode:
{control/check switch
set omega_required_mech}
according to appState:
{trigger appState Run/Stop/Init/
set PMSM Control Run/Stop
set Fault Control status
set Brake Control Run/Stop
set LED Indication}

Brake Control - Processing:

if u_dc_bus_filt > U_DCB_ON_BRAKE_SYSU
{Brake On}
if u_dc_bus_filt < U_DCB_OFF_BRAKE_SYSU
{Brake Off}

Figure 6-1. Software Flow Chart - General Overview I

The Switch process is split into Switch Filter Processing, called from Quadrature Timer D0 Interrupt
(see Figure 6-3); and Switch Get State, called from Application Control processing, which handles
manual switch control, and Switch Get State PC master software (in PC master application operating
mode).

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Interrupt
ADC Complete Interrupt
Down Button

Analog Sensing- Processing

according to anSensingCtrlStatus Down Button - ISR part:
sensing/initialization: if debounceCounterDown = 0:
{sense Temperature set UP_BUTTON, buttonStatus
calculate Filtered Temperature debounceCounterDown =
sense, correct 2 Phase Currents = DEBOUNCE_VALUE
calculate 3 Phase Currents
sense Voltage
correct Voltage Return
calculate Filtered Voltage}
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PMSM Control
-Current Processing: Interrupt
proceeds according to pmsmCtrlStatus Up Button

sin cos generation:

Up Button - ISR part:
get position from Position Mea-
if debounceCounterUp = 0:
surement
set UP_BUTTON, buttonStatus
sin (theta_actual_el)
debounceCounterUp =
cos (theta_actual_el)
= DEBOUNCE_VALUE

Current Control:
Currents Transformation (a,b,c to d-q) Return
(Field-Weakening Controller)
Current d Regulator
Current q Regulator
Voltages Transformation (d-q to α,β) Interrupt
DCBus Ripple Compensation PWM A Fault
Space Vector Module sets pwmABC
Fault Control - PWM Fault ISR part:
if Overcurrent or Overvoltage:
PWM:
{set appFaultStatus = Overvoltage /
set duty cycles to pwmABC
Overcurrent
triggers beginning of Fault State (disable PWM...)}

Analog Sensing-ADC Phase Set

set ADC converter phase current
Return
samples - two (easily measured)
phases

Return

Figure 6-2. Software Flow Chart - General Overview II

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Interrupt
D0 QTimer

Speed Measurement Processing

PMSM Control
Speed, Alignment Processing:
proceeds according to its status

get speed from Speed Measurement

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pmsmCtrlStatus?

AlignFlag RunFlag
others

Alignment: Speed Control:

Software Timer Software Timer
if Timeout if Timeout:
{PMSM Control - End Alignment} {Field-Weakening Controller
Speed Regulator
Speed Ramp}

LED Indication Processing

Switch Filter Processing

Button Processing - Interrupt part

decrements debounceCounterUp(Down)

Return

Figure 6-3. S/W Flow Chart - General Overview III

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6.2 Data Flow

The PM synchronous motor vector control drive control algorithm is described in the data flow charts
shown in Figure 6-4 and Figure 6-5. The variables and constants described should be clear from their
names.

Start/Stop Up/Down PC Green LED

Switch Buttons Master

omega_reqPCM_mech, appOpMode appState

appPcmCtrlStatus

LED
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Application
Indication
Control brakeCtrlStatus
faultCtrlStatus

appFaultStatus omega_required_mech pmsmCtrlStatus

i_Sa, i_Sb, i_Sc
anSensingCtrlStatus u_dc_bus
temperature
PHASEA,PHASEB,INDEX
temperature_filt
Analog Sensing
PC
(Temperature, DCBus volt.
Master Position, Speed Phase Currents a,b,c)
Software Measurement
u_dc_bus
i_Sabc_comp svmSector
omega_actual_mech theta_actual_el u_dc_bus_filt

theta_align_el_C i_Sd_Alignment
PMSM
Control
I_SDQ_MAX
reloadSWtmrSpeedControl
SVM_INV_INDEX,
reloadSWtmrAlignment pwmABC u_Reserve_FW

SVM_INV_INDEX,
u_OverMax
PWM Generation
coefBEMF, coefBEMFShift

PWM Outputs

Pwm_AT Pwm_AB Pwm_BT Pwm_BB Pwm_CT Pwm_CB

Figure 6-4. Data Flow - Part 1

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PWM Faults
TEMPERATURE_MAX_F16 (Overvoltage/Overcurrent)

temperature_filt
u_dc_bus_min_fault_C i_Sabc_comp
Check Index
Position
u_dc_bus_filt
faultCtrlStatus

Fault Control
u_dc_bus_on_brake
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Brake pmsmCtrlStatus appFaultStatus

Control PWMEN bit
PC
u_dc_bus_off_brake Master
Software

brakeCtrlStatus
PWM Generation
PWM Outputs

IO_BRAKE

Pwm_AT Pwm_AB Pwm_BT Pwm_BB Pwm_CT Pwm_CB

Figure 6-5. Data Flow - Part 2

The data flows consist of the processes described in the following sections.

6.2.1 Application Control Process

The Application Control process is the highest software level, which precedes settings for other
software levels.
The process state is determined by the variable appState.
The application can be controlled either:
• Manually
• From PC master software
The manual/PC master application operating mode is determined by the setting of appOpMode.
For manual control, the input of this process is the Run/Stop switch and Up/Down buttons.
The PC master software communicates via omega_reqPCM_mech, which is the required angular speed
from PC master software; appPcmCtrlStatus, which consists of the flags StartStopCtrl for Start/Stop;
RequestCtrl for changing the application’s operating mode appOpMode to manual or PC control; and
appFaultStatus, indicating faults.
The other processes are controlled by setting pmsmCtrlStatus, omega_required_mech,
appPcmCtrlStatus, brakeCtrlStatus, faultCtrlStatus.

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6.2.2 LED Indication Process

This process controls the LED flashing according to appState.

6.2.3 Analog Sensing Process

The Analog sensing process handles sensing, filtering and correction of analog variables (phase
currents, temperature, DC Bus voltage).

6.2.4 Position and Speed Measurement Process

The Position and Speed Measurement process gives mechanical angular speed omega_actual_mech
and electrical position theta_actual_el.

6.2.5 PMSM (PM Synchronous Motor) Control Process

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The PMSM (PM Synchronous Motor) Control process provides most of the motor control
functionality.
Figure 6-6 shows the data flow inside the process PMSM Control. It shows essential subprocesses of
the process: Sine; Cosine Transformations; Current Control; Speed; Alignment Control; and
Field-Weakening.
The Sine and Cosine Transformations generate sinCos_theta_el with the components sine, cosine
according to electrical position theta_actual_el. It is provided in a look-up table.

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omega_required_mech

Speed Ramp
reloadSWtmrAlignment Control reloadSWtmrSpeedControl

omega_actual_mech omega_desired_mech i_Sd_Alignment I_SDQ_MAX SVM_INV_INDEX,

u_Reserve_FW

PIRegParams_omega_mech.
theta_align_el_C PositivePILimit
Speed, Align
Control Field-Weakening
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theta_actual_el
u_SDQ
i_SDQ_desired i_SDQ_desired
Sin, Cos q_axis d_axis
Transformation
pmsmCtrlStatus u_dc_bus_filt
sinCos_theta_el

coefBEMF, coefBEMFShift
Current u_S_max_FWLimit
Control

i_Sabc_comp
svmSector

SVM_INV_INDEX, I_SDQ_MAX_F16 pwmABC

u_OverMax

Figure 6-6. Data Flow - PMSM Control

6.2.5.1 Current Control Process

The data flow inside the process Current Control is detailed in Figure 6-7. The measured phase
currents i_Sabc_comp are transformed into i_SDQ_lin using sinCos_theta_el; see Section 3.3.3. Both
d and q components are regulated by independent PI regulators to i_SDQ_desired values. The outputs
of the regulators are u_SDQ_lin.

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i_Sabc_comp sinCos_theta_el

Current Transformation
a,b,c -> d-q

i_SDQ_desired.q_axis i_SDQ.q_axis i_SDQ.d_axis i_SDQ_desired.d_axis

u_LimitF16 I_SDQ_MAX_F16
Current q Current d
Regulator Regulator
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omega_actual_mech
u_SDQ_lin.q_axis u_SDQ_lin.d_axis
pmsmCtrlStatus
coefBEMF, coefBEMFShift
Feed Forward

sinCos_theta_el u_SDQ
u_LimitF16

Voltage Transformation
d-q -> alpha, beta
SVM_INV_INDEX/2*
*u_dc_bus_filt +
+u_OverMax
u_SAlphaBeta

Scaling
DCBus Ripple
Compensation
u_dc_bus_filt SVM_INV_INDEX,
u_OverMax
u_Salpha_RipElim

Space Vector
Modulation

pwmABC svmSector

Figure 6-7. Data Flow - PMSM Control - Current Control

The Feed Forward process provides the following calculations:

coefBEMFShft
u_SDQ.q_axis = coefBEMF ⋅ 2 ⋅ omega_actual_mech + u_SDQ_lin.q_axis (EQ 6-1.)
u_SDQ.d_axis = u_SDQ_lin.d_axis (EQ 6-2.)

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The u_SDQ voltages are transformed into u_SAlphaBeta (see Section 3.3.3) by the Voltage
Transformation process. The Scaling DCBus Ripple Compensation block scales u_SAlphaBeta
(according u_dc_bus_filt) to u_Salpha_RipElim, described in the svmlimDcBusRip function in the
Motor Control Library. The space vector modulation process generates duty cycle pwmABC and
svmSector according to u_Salpha_RipElim.
The u_LimitF16 is a voltage limit for current controllers. The u_OverMax constant is used to increase
the limitation of u_SDQ voltages over maximum SVM_INV_INDEX/2*u_dc_bus_filt determined by
the DCBus voltage and space vector modulation. Although the pwmABC will be limited by the space
vector modulation process functions, the reserve is used for field-weakening controller dynamics. In
the stable state, the u_SDQ voltages vector will not exceed u_S_max_FWLimit; see Section 6.2.5.4.

6.2.5.2 Speed Ramp

The process generates angular speed omega_desired_mech from angular speed omega_required_mech
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with a linear ramp. The speed ramp is implemented so as not to saturate the speed regulator during
acceleration.

6.2.5.3 Speed, Alignment Control Process

The process controls the i_SDQ_desired.q_axis current according to the PMSM Control Process
Status.
For Alignment status, it sets i_SDQ_desired.d_axis to i_Sd_Alignment and i_SDQ_desired.q_axis to 0.
For Run status, it controls the omega_actual_mech speed to omega_desired_mech by calculation of
the PI regulator with i_SDQ_desired.q_axis output.

6.2.5.4 Field-Weakening Process

u_dc_bus_filt SVM_INV_INDEX u_Reserve_FW

SVM_INV_INDEX/2*u_dc_bus_filt-u_Reserve_FW

0 - I_SDQ_MAX_F16
u_S_max_FWLimit

u_SD.d_axis +
max limit min limit i_SDQ_desired.d_axis
-
(d_axis2+q_axis2)1/2
u_SD.q_axis PI regulator

Figure 6-8. Field-Weakening Controller

The field-weakening process provides control of i_SDQ_desired.d_axis in order to achieve higher

motor speeds by the field-weakening technique. The control algorithm is shown in Figure 6-8. The
u_S_max_FWLimit is computed from u_dc_bus_filt. The u_Reserve_FW is subtracted, in order to have
some voltage reserve, to the maximum SVM_INV_INDEX/2*u_dc_bus_filt determined by DCBus
voltage and space vector modulation. The reserve is used for field-weakening controller dynamics; in
the stable state, the u_SDQ voltages vector will not exceed u_S_max_FWLimit.

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This process also provides voltage limitation i_SDQ_desired.d_axis2 + i_SDQ_desired.q_axis2 <

(I_SDQ_MAX_F16)2 by setting:
2 2
PIRegParams_omega_mech.PositivePILimit = I_SDQ_MAX_F16 – i_SDQ_desired.d_axis (EQ 6-3.)
2 2
PIRegParams_omega_mech.NegativePILimit = – I_SDQ_MAX_F16 – i_SDQ_desired.d_axis (EQ 6-4.)

6.2.6 Brake Control Process

The brake control process maintains DCBus voltage level via the IO_BRAKE driver, which controls
the brake switch. The voltage comparison levels are u_dc_bus_on_brake, which is initialized with
either the U_DCB_ON_BRAKE_MAINS230_F16 or U_DCB_ON_BRAKE_MAINS115_F16 constant
according to mains voltage, and u_dc_bus_off_brake, initialized with
U_DCB_OFF_BRAKE_MAINS230_F16 or U_DCB_OFF_BRAKE_MAINS115_F16.
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6.2.7 PWM Generation Process

The PWM generation process controls the generation of PWM signals, driving the 3-phase inverter.
The input is pwmABC, with three PWM components scaled to the range <0,1> of type Frac16. The
scaling (according to PWM module setting) and the PWM module control (on the DSP) is provided by
the PWM driver.

6.2.8 Fault Control Process

The Fault Control process checks the Overheating, Undervoltage, Overvoltage, Overcurrent and
Position Sensing faults.
Overheating and Undervoltage are checked by the comparisons temperature_filt <
TEMPERATURE_MAX_F16 and u_dc_bus_filt < u_dc_bus_min_fault_C, where
u_dc_bus_min_fault_C is initialized with U_DCB_MIN_FAULT_MAINS230_F16 or
U_DCB_MIN_FAULT_MAINS115_F16. The Position Sensing fault is checked with the Check Index
Position process.
The Overvoltage and Overcurrent faults are set in the PWMA Fault interrupt.

6.3 State Diagram

The software can be split into the processes shown in Section 6.2.
The following processes are described below:
• Application Control State Diagram
• PMSM Control State Diagram
• Fault Control State Diagram
• Analog Sensing State Diagram
All processes start with the DSP Initialization state after Reset.

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6.3.1 DSP Initialization

The DSP Initialization state:
• Initializes:
— PWM
— Application Control
— PM Synchronous Motor Control
— Analog Sensing
— Brake Control
— Fault Control
— LED Indication
— Button Control
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• Sets manual application operating mode

• Enables masked interrupts
• Application Control: Initialization Triggers, which set all affected processes to the Begin
Application Initialization state

6.3.2 Application Control State Diagram

The Application Control process is detailed in Figure 6-9.

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Reset

DSP
Initialization

done

Application Control:
switchState = Stop &
Fault Control: faults cleared Init
Initializations proceeding
appState = APP_INIT
Init Fault Control (pcb identification)
set appOpMode
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Application Control: appPcmCtrlStatus. switchState = Stop &

Fault RequestCtrl = 1 initializations finished
Fault Control:
Begin Fault switchState = Run
done Application Control:
Application Control: Stop
Application Control:
Fault Begin appState = APP_STOP
Begin Run
clear pmsmCtrlStatus.RunFlag set appState = APP_RUN
clear pmsmCtrlStatus.AlignFlag done
set appState = APP_FAULT
done
Application Control:
Begin Stop
Application Control:
set appState = APP_STOP
Run
appState = APP_RUN

switchState = Stop
Fault Control: Begin Fault

Figure 6-9. State Diagram - Application Control

After reset, the DSP Initialization state is entered. The peripherals and variables are initialized in this
state, and the application operating mode appOpMode is set to Manual Control.
When the state is finished, the Application Control Init state follows. As shown in Figure 6-9,
appState = APP_INIT; all subprocesses requiring initialization are proceeding; pcb identification is
provided; the PWM is disabled; and so no voltage is applied on motor phases. If the
appPcmCtrlStatus.RequestCtrl flag is set from PC master software, the application operating mode
appOpMode is toggled and the application operating mode can only be changed in this state. If the
switchState = Stop, the Application Control enters the Stop state.
The switchState is set according to the manual switch on the EVM or PC master software register
AppPcmCtrlStatus.StartStopCtrl, depending on the application operating mode.
In the Stop state, appState = APP_STOP and the PWM is disabled, so no voltage is applied on motor
phases. When switchState = Run, the Begin Run state is processed. If there is a request to change
application operating mode, appPcmCtrlStatus.RequestCtrl = 1, the application Init is entered and the
application operating mode request can only be accepted in the Init or Stop state by transition to the
Init state.
In the Begin Run state, all the processes provide settings to the Run state.

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In the Run state, the PWM is enabled, so voltage is applied on motor phases. The motor is running
according to the state of all subprocesses. If switchState = Stop, the Stop state is entered.
If and fault is detected during the Begin Fault state, which is a subprocess of Fault control, the Begin
Fault state is entered. It sets appState = APP_FAULT; the PWM is disabled; and the subprocess
PMSM Control is set to Stop. The Fault state can only move onto the Init state when switchState =
Stop, and the Fault Control subprocess has successfully cleared all faults.

6.3.3 PMSM Control State Diagram

A state diagram of the Commutation Control process is illustrated in Figure 6-10.

Application Control: Init

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PMSM Control:
Initialization
clear AlignInitDoneFlag

Application Control: Begin Running

done pmsmCtrlStatus.AlignInitDoneFlag = No

done PMSM Control: PMSM Control:

Stop or Fault Begin Alignment
set Alignment current
PMSM Control: set Alignment timeout
Begin Running
Begin Stop or Fault set AlignFlag done
AlignInitDoneFlag = 1
clear RunFlag
clear AlignFlag
Application Control: Begin Stop/Fault PMSM Control:
Alignment
timeout search
Current ramp
done
PMSM Control:
PMSM Control: Alignment Timeout
Begin Run
Run set RunFlag PMSM Control:
End Alignment
done Set Zero Position
set AlignInitDoneFlag
clear AlignFlag

Figure 6-10. State Diagram - PMSM Control

When Application Control initializes, the PMSM Control subprocess initialization state is entered. The
AlignInitDoneFlag is cleared, which means that alignment can proceed. The next PMSM Control state
is Begin Stop or Fault. RunFlag and AlignFlag are cleared and the Stop or Fault state is entered. When
Application Control: Begin Run, the PMSM Control subprocess enters the Begin Alignment or Begin
Run state, depending on whether or not the alignment initialization has already proceeded (flagged by
AlignInitDoneFlag). The alignment state is necessary for setting the zero position of position sensing;
see Section 4.3.1.3. In the state Begin Alignment, the Alignment current and duration are set; the
alignment is provided by setting desired current for d_axis to i_Sd_Alignment and q_axis to 0. The

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alignment state provides current control and timeout search. When alignment timeout occurs, End
Alignment is entered. In that state, the Position Sensing Zero Position is set, so the position sensor is
aligned with the real vector of the rotor flux. When the End Alignment state ends, the PMSM Control
enters a regular Run state, where the motor is running at the required speed. If the Application Control
state is set to Begin Stop or Begin Fault, the PMSM Control enters the Begin Stop or Fault, then the
Stop or Fault.

6.3.4 Fault Control State Diagram

The state diagram of the Fault Control subprocess is illustrated in Figure 6-11. After the initialization,
the fault conditions are searched. If any fault occurs, the appFaultStatus variable is set according to
detected error; PWM is switched on (PWMEN bit = 0); the Fault state is entered. This state also causes
Application Control: Fault state. If the faults are successfully cleared, this is signaled to the
Application Control process. The Fault state is left when the Application Control Init state is entered.
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Reset

Fault Control:
DSP Initialization

Application Control: Init

Fault Control:
Application Initialization
clear appFaultStatus
pcb identification

done

Fault Control:
No Fault
searching faults
Fault:
Undervoltage (filtered)
Overheating (filtered)
Overcurrent (fault pin)
Overvoltage (fault pin)
wrong PCB
Position Sensing fault
Fault Control:
Begin Fault
Application Control Begin Fault
setting of appFaultStatus
PWMEN bit = 0

done

Fault Control:
Fault
clear/test faults

Figure 6-11. State Diagram Fault Control

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Implementation Notes

6.3.5 Analog Sensing State Diagram

The state diagram of the Analog Sensing subprocess is shown in Figure 6-12. The DSP Initialization
state initializes hardware modules like ADC, synchronization with PWM, etc. In Begin Init,
Initialization is started, so the variables for initialization sum and the InitDoneFlag are cleared. In the
Init Proceed state, the temperature, DCBus voltage and phase current samples are sensed and summed.
After required analog sensing, Init samples are sensed, and the Init Finished state is entered. There, the
samples’ average is calculated, from the sum divided by the number of analog sensing Init samples.
According to the phase currents’ average value, the phase current offsets are initialized.
All variable sensing is initialized and the state Init Done is entered, so the variables from analog
sensing are valid for other processes. In this state, temperature and DCBus voltage are filtered in first
order filters.

Reset
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Analog Sensing
DSP Initialization

Application Control: Begin Init

Analog Sensing: done Analog Sensing

Begin Init
Init. Proceed:
clear variables
sense and sum samples
clear InitDoneFlag
count samples
samples counter =
Application Control: Begin Init analog sensing init samples

Analog Sensing
Analog Sensing
Init Finished:
Init Done,
samples average
normal operation:
set current offsets
done
set InitDoneFlag

Figure 6-12. State Diagram - Analog Sensing

7. Implementation Notes
7.1 Scaling of Quantities
The PM synchronous motor vector control application uses a fractional representation for all real
quantities except time.
The N-bit signed fractional format is represented using 1.[N-1] format (1 sign bit, N-1 fractional bits).
Signed fractional numbers (SF) lie in the following range:
–[ N – 1 ]
– 1.0 ≤ SF ≤ +1.0 -2 (EQ 7-1.)
For words and long-word signed fractions, the most negative number that can be represented is -1.0,
whose internal representation is $8000 and $80000000, respectively. The most positive word is $7FFF
or 1.0 - 2-15, and the most positive long-word is $7FFFFFFF or 1.0 - 2-31.

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Implementation Notes

The following equation shows the relationship between the real and fractional representations:
Real Value
Fractional Value = -------------------------------------------------------------- (EQ 7-2.)
Real Quantity Range Max
where:
Fractional Value is the fractional representation of the real value [Frac16]
Real Value is the real value of the quantity [V, A, RPM, etc.]
Real Quantity Range Max is the maximum of the quantity range, defined in the application [V, A,
RPM, etc.]
The C language standard does not have any fractional variable type defined. Therefore, fractional
operations are provided by CodeWarrior intrinsics functions (e.g. mult_r() ). As a substitution for the
fractional type variables, the application uses types Frac16 and Frac32. These are in fact defined as
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integer 16-bit signed variables and integer 32-bit signed variables. The difference between Frac16 and
pure integer variables is that Frac16 and Frac32 declared variables should only be used with fractional
operations (intrinsics functions).
A recalculation from real to a fractional form and Frac16, Frac32 value is made with the following
equations:

Real Value
Frac16 Value = 32768 ⋅ -------------------------------------------------------------- (EQ 7-3.)
Real Quantity Range Max

for Frac16 16-bit signed value and:

31 Real Value
Frac32 Value = 2 ⋅ -------------------------------------------------------------- (EQ 7-4.)
Real Quantity Range Max

for Frac32 32-bit signed value.

Real Value
Fractional Value = -------------------------------------------------------------- (EQ 7-5.)
Real Quantity Range Max

Fractional form, a conversion from Fraction Value to Frac16 and Frac32 Value can be provided by the
C language macro.

7.1.1 Voltage Scaling

Voltage scaling results from the sensing circuits of the hardware used; for details see the 3-Phase
AC/BLDC High-Voltage Power Stage User’s Manual.
Voltage quantities are scaled to the maximum measurable voltage, which is dependent on the
hardware. The relationship between real and fractional representations of voltage quantities is:
u Real
u Frac = -------------------------------------------------------
- (EQ 7-6.)
VOLT_RANGE_MAX

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Implementation Notes

where:
uFrac Fractional representation of voltage quantities [-]
uReal Real voltage quantities in physical units [V]
VOLT_RANGE_MAX Defined voltage range maximum used for scaling in physical units[V]

In the application, the VOLT_RANGE_MAX value is the maximum measurable DCBus voltage:
VOLT_RANGE_MAX = 407 V
All application voltage variables are scaled in the same way (u_dc_bus, u_dc_bus_filt, u_SAlphaBeta,
u_SDQ, u_SAlphaBeta, and so on).

7.1.2 Current Scaling

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Current scaling also results from the sensing circuits of the hardware used; for details see 3-Phase
AC/BLDC High-Voltage Power Stage User’s Manual.
The relationship between real and fractional representation of current quantities is:
i Real
i Frac = --------------------------------------------------------
- (EQ 7-7.)
CURR_RANGE_MAX

where:
iFrac Fractional representation of current quantities [-]
iReal Real current quantities in physical units [A]
CURR_RANGE_MAX Defined current range maximum used for scaling in physical units[A]
In the application, the CURR_RANGE_MAX value is the maximum measurable current:
CURR_RANGE_MAX = 5.86 A
All application current variables are scaled in the same way (components of i_Sabc_comp,
i_SAlphaBeta, i_SDQ, i_SDQ_desired, i_Sd_Alignment and so forth).

Note: As shown in 3-Phase AC/BLDC High-Voltage Power Stage User’s Manual, the current
sensing circuit provides measurement of the current in the range from CURR_MIN = -2.93A
to CURR_MAX = +2.93A, giving the voltage for the ADC input ranges from 0 to 3.3V with
1.65V offset. The DSP5680x’s ADC converter is able to automatically cancel (subtract) the
offset. The fractional representation of the measured current is then in the range <-0.5, 0.5),
while the possible representation of a fractional value is <-1,1), as shown in (EQ 7-3.).
Therefore, CURR_RANGE_MAX is calculated according to the following equation:

CURR_RANGE_MAX = CURR_MAX-CURR_MIN = 2 ⋅ CURR_MAX (EQ 7-8.)

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Implementation Notes

7.1.3 Speed Scaling

Speed quantities are scaled to the defined speed range maximum, which should be set lower than all
speed variables in the application, so it was set higher than the maximum mechanical speed of the
drive. The relationship between real and fractional representation of speed quantities is:
ω Real
ω Frac = -------------------------------------------------------------
- (EQ 7-9.)
OMEGA_RANGE_MAX

where:
ωFrac Fractional representation of speed quantities [-]
ωReal Real speed quantities in physical units [rpm]
OMEGA_RANGE_MAX Defined speed range maximum used for scaling in physical units[rpm]
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In the application, the OMEGA_RANGE_MAX value is defined as:

OMEGA_RANGE_MAX = 6000rpm
Other speed variables are scaled in the same way (omega_reqPCM_mech, omega_desired_mech,
omega_required_mech, omega_reqMAX_mech, omega_reqMIN_mech, omega_actual_mech).
The relation between speed scaling and speed measurement with encoder is described in
Section 4.3.1.2. In the final software, the constant OMEGA_SCALE is identical with the scaling
constant k in equations (EQ 4-1.) and (EQ 4-3.), and OMEGA_RANGE_MAX is ωMax.

7.1.4 Position Scaling

Position Scaling is described in Section 4.3.1.1

7.1.5 Temperature Scaling

As shown in Section 4.3.4, the temperature variable does not have a linear dependency.

7.2 PI Controller Tuning

The application consists of four PI controllers. Two controllers are used for the Id and Iq currents, one
for speed control and the other for field-weakening. The controller’s constants are given by simulation
in Mathlab and were experimentally specified. A detailed description of controller tuning is beyond the
scope of this application note.

7.3 Subprocesses Relation and State Transitions

As shown in Section 6.2 and Section 6.3, the software is split into subprocesses according to
functionality. The application code is designed to be able to extract individual processes, such as
Analog Sensing, and use them for customer applications. The C language functions dedicated for each
process are located in one place in the software, so they can be easily used for other applications. The
function naming usually starts with the name of the process, for example, AnalogSensingInitProceed().
As Section 6.3 shows, the processes’ or subprocesses’, state transients have some mutual relations. For
example, Application Control: Begin Initialization is a condition for transient of the Analog Sensing
process: Init Done to Begin Init state. In the code, the interface between processes is provided via
“trigger” functions. The naming convention is for these functions is: <ProcessName><State>Trig().

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Implementation Notes

The functionality will be explained in following example:

The “trigger” function Process1StateTrig() is called from process1. The transient functions of
process2, process3,etc., which must be triggered by Process1State, are put inside the
Process1StateTrig().

7.4 Run/Stop Switch and Button Control

In the DSP56F805EVM and the DSP56F807EVM, the Run/Stop switch is connected to a GPIO pin.
The state of the Run/Stop switch can be read directly from the GPIO Data Register. In the
DSP56F803EVM, there are fewer free GPIO pins, so the switch is connected to ADC input AN7 and
the switch status is obtained with the AD Converter. The switch logical status is obtained by
comparing the measured value with the threshold value.
Also, the buttons are usually connected to GPIO pins. But in this application, the buttons are connected
to IQRA and IRQB interrupts to allow the ability to run the same code on the DSP56F803,
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DSP56F805, and DSP56F807 EVMs. Since the DSP56F803 has no free GPIO pins for user buttons,
the application uses buttons connected to IRQA/B pins. The EVM boards do not resolve the button
contact bouncing, which may occur while pushing and releasing the button, so this issue must be
resolved by software.
The IRQA and IRQB interrupts are maskable interrupts connected directly to the DSP’s core. The
IRQA and IRQB lines are internally synchronized with the processor’s internal clock and can be
programmed as level-sensitive or edge-sensitive. The IRQA and IRQB interrupts have no interrupt
flag, so this flag is replaced by a software flag. The following algorithm is used to check the state of
the IRQ line and is described for one interrupt.
The IRQ interrupt is set to be negative-level-sensitive. When the button is pressed, the logical level 0 is
applied on the IRQ line and the interrupt occurs; see Figure 7-1. To avoid multiple calls of ISR due to
contact bounces, the ISR disables the IRQ interrupt, sets the debounce counter to a predefined value
and sets the variable buttonStatus to 1. The variable buttonStatus represents the interrupt flag. Using
the DSP56F80x’s software timer, the ButtonProcessing function is periodically called, as shown in
Figure 7-1. The function ButtonProcessing decrements the debounce counter and if the counter is 0,
the IRQ interrupt is again enabled. The button press is checked by the ButtonEdge function; see
Figure 7-2. When the variable buttonStatus is set, the ButtonEdge function returns “1” and clears
buttonStatus. When the variable buttonStatus is not set, the ButtonEdge function returns “0”.
According to the ButtonProcessing calling period, the value of the debounce counter should be set
close to 180ms. This value is sufficient to prevent multiple IRQ ISR calls due to contact bounces.

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Implementation Notes

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Figure 7-1. Button Control - IRQ ISR and ButtonProcessing

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Figure 7-2. Button Control - ButtonEdge

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SDK Implementation

8. SDK Implementation
The Motorola Embedded SDK is a collection of APIs, libraries, services, rules and guidelines. This
software infrastructure is designed to let DSP5680x software developers create high-level, efficient,
portable code. The application code is available in the SDK. This chapter describes how the PM
synchronous motor vector control application is written under the SDK.

8.1 Drivers and Library Function

The PM synchronous motor vector control application uses the following drivers:
• ADC driver
• Quadrature Timer driver
• Quadrature Decoder driver
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• PWM driver
• LED driver
• SCI driver
• PC master software driver
• Switch driver (only for DSP56F805EVM and DSP56F807EVM)
• Brake driver
All drivers are included in bsp.lib library.
The PM synchronous motor vector control application uses the following library functions:
• cptrfmClarke (Clarke transformation, mcfunc.lib library)
• cptrfmPark (Park transformation, mcfunc.lib library)
• cptrfmParkInv (Inverse Park transformation, mcfunc.lib library)
• mcElimDcBusRip (DC bus ripple elimination, mcfunc.lib library)
• mcPwmIct (3-ph sinewave modulation, mcfunc.lib library)
• rampGetValue (ramp generation, mcfunc.lib library)
• switchcontrol (switch control, mcfunc.lib library)
• boardId (board identification, bsp.lib library)

8.2 Appconfig.h File

The purpose of the appconfig.h file is to provide a mechanism for overwriting default configuration
settings, which are defined in the config.h file.
There are two appconfig.h files. The first appconfig.h file is dedicated for External RAM
(..\ConfigExtRam directory) and second one is dedicated for Flash memory (..\ConfigFlash directory).
In the PM synchronous motor vector control application, both files are identical, with these exceptions:
• The appconfig.h for the ExtRAM target contains a definition of the RAM memory support
• The appconfig.h for the Flash target contains a definition of the FLASH support
• The appconfig.h for the ExtRAM target contains a PC master software recorder buffer 25000
samples long, while appconfig.h for the Flash target contains a PC master software recorder
buffer for only 100 samples, due to the limited Flash memory size
• The appconfig.h for the DSP56F805EVM and DSP56F807EVM contains the definition of a
switch driver, while the appconfig.h for the DSP56F803EVM does not

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SDK Implementation

The appconfig.h file can be divided into two sections. The first section defines which components of
SDK libraries are included in the application; the second part overwrites components’ standard setting
during their initialization.

8.3 Drivers’ Initialization

Each peripheral on the DSP chip or on the EVM board is accessible through a driver. The driver
initialization of all peripherals used is described in this section. For a more-detailed description of
drivers, see the Targeting Motorola DSP5680x Platformm manual.
To use a driver, following these steps:
• Include the driver support to the appconfig.h
• Fill the configuration structure in the application code for specific drivers, which depends on
driver type
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• Initialize the configuration setting in appconfig.h for specific drivers, which depends on driver
type
• Call the open (create) function
Access to individual driver functions is provided by the ioctl function call.

8.4 Interrupts
The SDK serves the interrupt routine calls and automatically clears interrupt flags. The user defines the
callback functions called during interrupts. The callback functions are assigned during driver
initialization--open(). The callback function assignment is defined as one item of the initialization
structure, which is used as a parameter of the open()function. Some drivers define the callback
function in the appconfig.h file.

8.5 PC Master Software

PC master software was designed to provide a debugging, diagnostic and demonstration tool for
development of algorithms and applications. It consists of components running on PCs and parts
running on the target DSP, connected by an RS-232 serial port. A small program is resident in the DSP
that communicates with the PC master software to parse commands, return status information to the
PC, and process control information from the PC. The PC master software executing on a PC uses
Microsoft Internet Explorer as a user interface to the PC.
The PC master software application is a part of the Motorola Embedded SDK and may be selectively
installed during SDK installation.
To enable the PC master software operation on the DSP target board application, add the following
lines to the appconfig.h file:
#define INCLUDE_SCI /* SCI support */
#define INCLUDE_PCMASTER /* PC master software support */
It automatically includes the SCI driver and installs all necessary services.
The default baud rate of the SCI communication is 9600 and is set automatically by the PC master
software driver.
A detailed PC master software description is provided in the PC Master Software User’s Manual.

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SDK Implementation

The 3-Phase PM Synchronous Motor Vector Control utilizes PC master software for remote control
from a PC. It enables the user to:
• Control the PC master software
• Start/stop control
• Set the motor speed
Variables read by the PC master software as a default and displayed to the user are:
• Required Speed of the motor
• Actual Speed of the motor
• Application status
— Init
— Stop
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— Run
— Fault
• DCBus voltage level
• Identified line voltage
• Fault Status
— No_Fault
— Overvoltage
— Overcurrent
— Undervoltage
— Overheating
• Identified Power Stage
The profiles of required and actual speeds, together with the desired Id and Iq currents can be seen in
the Speed Scope window.
The course of quickly-changing variables can be observed in the Recorder windows, displayed by the
PC master’s Speed Scope. The Recorder can only be used when the application is running from
External RAM, due to the limited on-chip memory. The length of the recorded window may be set in
Recorder Properties => bookmark Main => Recorded Samples. The dedicated memory space is
defined in the appconfig.h file of the ExtRAM target. The recorder samples are taken every 125µsec.
The following records can be captured:
• Required speed
• Actual speed
• Desired Id current
• Desired Iq current
The PC master software Control Page is illustrated in Figure 8-1. The profiles of the required and
actual speeds can be seen in the Speed Scope window.

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DSP Memory Use
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Figure 8-1. PC Control Window

9. DSP Memory Use

Table 9-1 shows how much memory is needed to run the 3-phase PM Synchronous Vector Control
drive using the quadrature encoder. A part of the DSP memory is still available for other tasks.

Table 9-1. RAM and FLASH Memory Use by SDK2.4 and CW4.1
Memory Available for Available for Application Used + Application Used
(in 16-bit Words) DSP56F803 DSP56F807 Stack without PC Master
DSP56F805 Software, SCI

Program FLASH 32K 60K 11520 7740

Data FLASH 4K 8K 617 617

Program RAM 512 2K 36 36

Data RAM 2K 4K 745 + 352 stack 452 + 352 stack

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10. References
[1] Design of Brushless Permanent-magnet Motors, J.R. Hendershot JR and T.J.E. Miller, Magna
Physics Publishing and Clarendon Press, 1994
[2] Brushless DC Motor Control using the MC68HC708MC4, AN1702/D, John Deatherage and Jeff
Hunsinger, Motorola
[3] DSP56F803 Evaluation Module Hardware User’s Manual, DSP56F803EVMUM/D, Motorola
[4] DSP56F805 Evaluation Module Hardware User’s Manual, DSP56F805EVMUM/D, Motorola
[5] DSP56F807 Evaluation Module Hardware User’s Manual, DSP56F807EVMUM/D, Motorola
[6] 3-Phase AC/BLDC High-Voltage Power Stage User’s Manual, MEMC3PBLDCPSUM/D,
Motorola, 2000
[7] DSP56F800 Family Manual, DSP56F800FM/D, Motorola
[8] DSP56F801 - 7 User’s Manual, DSP56F801-7UM/D, Motorola
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[9] Evaluation Motor Board User’s Manual, MEMCEVMBUM/D, Motorola

[10] User’s Manual for PC master software, included in the SDK documentation, Motorola, 2001
[11] Embedded Software Development Kit for 56800/56800E, MSW3SDK000AA, available on
Motorola SPS web page, Motorola, 2001
[12] Sensorless Vector and Direct Torque Control, P. Vas (1998), Oxford University Press, ISBN
0-19-856465-1, New York.
[13] Elektricke pohony, Caha, Z.; Cerny, M. (1990), SNTL, ISBN 80-03-00417-7, Praha.
[14] Motorola SPS web page: http://www.motorola.com/semiconductor

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